1. Field of the Invention
The present invention concerns a support for fitting a shrinkable sleeve tightly to an object to be covered.
2. Description of the Prior Art
This type of support is known in itself and is used, among other things, to fit a sleeve over a cable termination or over a joint between two cables or over any object onto which a sleeve is to be shrunk. The support initially carries the prestretched sleeve and is mounted over the object to position the sleeve over the object. It is then removed to place the sleeve directly over the object whereupon it shrinks into place.
Document FR-A-2 592 825 describes one embodiment of a support of this kind comprising a tube which is removed from under the prestretched sleeve to fit the sleeve over a member inside it. According to this document, a slippery film covers the exterior surface of the tube over at least part of its length. The film is fixed to a front end of the tube and is not attached to the exterior surface of the tube; it is trapped between the prestretched sleeve and the tube. The tube is removed by pulling on its rear end which advantageously is not covered by the film.
As the tube is withdrawn the sleeve shrinks into place on the object, with the film doubling back on itself between the sleeve and the object. When the tube has been completely extracted from under the sleeve, the film is in turn removed by further movement of the tube.
In practise, a support of this kind is used when the sleeve is relatively short and/or relatively thin. If the sleeve is long and/or thick a two-part support is used, the two parts of which are two tubes like the tube described above, independent of each other and abutted head-to-head to carry the prestretched sleeve. To fit the sleeve the two parts are withdrawn from under the sleeve one after the other.
The problem with a double-tube support of this type is that when the first of the two tubes is withdrawn the second tube tends to move with it on the object. This leads to incorrect positioning of the sleeve on the object.
Document US-A-3 515 798 describes another embodiment of a support of this kind, in the form of a spiral tube. The spiral tube has continuous spiral turns joined together along their length to define linked tubular parts equal in number to the turns in the single spiral tube.
The spiral tube is withdrawn from the prestretched sleeve by pulling on the turn at the front end and on the subsequent turns, from the rear end of the tube, to dismantle the tube. A lug joined to the front turn extends for this purpose through the inside of the tube and beyond its rear end.
Document WO 93/22816 also describes a spiral tube support with annular turns which define a serpentine between them to separate the turns alternately in one direction and in the opposite direction.
These spiral supports have the same problem as the two-part supports and tend to move on the object when they are dismantled to remove them from under the sleeve, with the result that the sleeve is fitted incorrectly.
An object of the present invention is to solve this problem and thereby to enable correct fitting of the shrinkable sleeve.